IBD Symptoms

Inflammatory Dowel Disease in Dogs

Inflammatory Dowel Disease (IBD) symptoms can include diarrhea, vomiting, nutrient malabsorption, weight loss, lethargy, abdominal pain, nausea, depression, poor appetite, stomach gurgling, bloating, anemia, and fever.

IBD is characterized by inflammatory immune system cells that infiltrate the lining of the gastrointestinal tract, resulting in inflammation.

This chronic inflammation leads to a gradual thickening of the bowel lining as scar-like fibrous tissue replaces healthy tissue.

The thickening of the intestinal wall disrupts normal bowel function by interfering with the intestine's ability to contract, move food around, and absorb nutrients.

IBD Symptoms by Inflammation Location

The specific IBD symptoms a dog will experience depend on where in the gastrointestinal tract the inflammation is located.

Gastritis - Inflammation of the stomach is known as gastritis. In the case of chronic gastritis, IBD symptoms typically consist of vomiting, nausea, lack of appetite, and lethargy, but the patient won't experience diarrhea if the inflammation is limited to the stomach lining. The dog's temperature may be slightly elevated. Vomit can contain bits of undigested or partially digested food, but on other occasions, dogs will be throwing up pure liquid. Blood may be present as well.

Enteritis - This is an inflammation of the small intestine. The higher up in the small intestine the inflammation is located, the greater the likelihood of chronic vomiting. Vomit may consist of bile, foam, liquid, or food.

Other IBD symptoms where the cause is chronic enteritis include diarrhea, nutrient malabsorption, weight loss, abdominal pain, and lethargy. Stools tend to be in large in volume, very loose and watery, and may contain bits of undigested food, particularly fat; however, dogs usually do not defecate with increased urgency, and the frequency of bowel symptoms is normal or only slightly elevated.

Blood may or may not be present in stools, but if it is, it will be dark, not bright red.

Because the bulk of nutrient absorption occurs in the small intestine, chronic inflammation in this part of the GI tract tends to have the most profoundly negative effects on the dog's overall health.

Colitis - In the case of colitis, the large intestine is at the center of the inflammation.

Diarrhea is the primary IBD symptom resulting from the inflammation of the large intestine.

This type of diarrhea is characterized by increased frequency and, often, increased urgency to defecate coupled with straining to have a bowel movement. The dog may actually appear to be constipated, but when the stool finally arrives, it's loose or semi-formed. A pudding-like consistency is typical.

Stools also tend to contain lots of mucous and may be small in volume. Blood may or may not be present, but when it is, it looks fresh and bright red or slightly rust-colored.

Unlike dogs with gastritis or enteritis, dogs with colitis often appear healthy, happy, and active with good appetite. However, in severe chronic cases, the colon can become so inflamed that defecation becomes painful. In that event, some dogs will attempt to avoid having bowel movements, which can result in alternating periods of constipation and diarrhea.

While less common and less pronounced than what's seen with upper GI tract involvement, severe ongoing colitis can also cause vomiting and gradual weight loss. Dehydration and vitamin deficiencies are also possible, as the intestinal microbial balance is disturbed and the beneficial bacteria responsible for the production of certain essential vitamins are no longer present in adequate numbers.

Many dogs with IBD experience inflammation in more than one area of the GI tract, so a combination of symptoms is not uncommon. IBD symptoms may seem to improve or even disappear for short periods, but they eventually return and usually worsen over time.

IBD Diagnosis

I often have IBD in mind when I'm presented with a dog who's had repeated episodes of abdominal discomfort or pain accompanied by diarrhea, vomiting, or a noisy stomach. However, the only way to definitely diagnose IBD is through a biopsy. Since biopsies are invasive procedures (not to mention being rather expensive), it is standard practice to first run a series of diagnostic tests in order to rule out other potential causes of the symptoms.

We usually begin with blood work, consisting of a chemistry panel and CBC (Complete Blood Count). Most dogs with IBD have normal chemistry panels and CBC values, but the laboratory findings can help identify systemic disorders such as liver or kidney disease that could be causing the symptoms. A vitamin B12 (cobalamin) and folate test may also be indicated where intestinal malabsorption due to IBD is suspected.

Radiographs may be used to examine the intestines, but even when a thickening of the intestinal wall is apparent, this is not necessarily evidence of IBD. Radiographs can, however, be useful to detect gastrointestinal growths and tumors that could be causing the symptoms.

Urinalyses and fecal tests are also part of the complete work-up your vet is likely to perform if he or she suspects IBD. Since some of the intestinal worms (e.g., hookworms, whipworms) and protozoa (e.g., Giardia, Cryptosporidium) that can cause IBD symptoms can be difficult to detect, your vet may administer a broad-spectrum parasiticide such as fenbendazole on a presumptive basis. Bacterial cultures may also be taken, and if your vet suspects bacterial overgrowth, he or she will likely prescribe a course of antibiotics to see if it helps.

Food allergies and intolerances must be ruled out, so a food trial or hypoallergenic diet will be indicated. This can be a commercial limited ingredient dog food or a home-cooked diet. What's important is that the food contains only ingredients the dog has not eaten before. Typically, a single protein source and a single gluten-free carbohydrate source are selected for the food trial, and no other ingredients--including treats or supplements--must be fed.

The vast majority of dogs who respond to the change in diet will start showing clear signs of improvements within 2-3 weeks, but in about 5% of dogs, it can take up to 6 weeks before improvements are noted, and in a very small minority, mainly consisting of Labrador Retrievers and Cocker Spaniels, it can take 10-12 weeks to see positive results. Unfortunately, a positive response to the food trial does not rule out IBD. Dogs with IBD may initially experience a reduction in symptoms when switched to the limited ingredient diet, but these improvements are usually temporary.

Ultimately, if no other cause of the IBD symptoms can be found, your vet will likely recommend an endoscopic biopsy to confirm the suspected IBD diagnosis. Less commonly, a surgical biopsy is performed instead. Either way, during the biopsy tissue samples are collected from different parts of the GI tract. If elevated numbers of inflammatory cells are found in the intestinal wall, the IBD diagnosis is confirmed. A pathologist then grades the severity of the infiltration of inflammatory cells and identifies the type of cells present. The latter will determine the form of IBD your dog has.

Lymphocytic-plasmacytic IBD (LPIBD) is the most common form of IBD. Eosinophilic IBD is the second most common. It is also generally considered the most severe form of IBD. Less common are Neutrophilic (or Suppurative) IBD, Regional Granulomatous, and Histiocytic Ulcerative Colitis. The latter occurs almost exclusively in boxers.

What Causes IBD?

The short answer is: We don't know. Something is continually stimulating an immune response, leading to chronic inflammation, but what that something is isn't clear, nor is it likely that the culprit is the same in every case. On the contrary, the most likely explanation is that IBD has multiple causes and may even have multiple causes in the same individual.

That said, because the problem revolves around the chronic stimulation of the immune system, IBD is usually considered an immune-mediated disorder. It is believed that the gastrointestinal tract is initially sensitized by parasites, bacteria, fungi, food particles, or some other antigen or combination of antigens.

The immune system considers these antigens foreign invaders and mounts an allergic-type immune response to destroy them. Since these antigens are processed through the lining of the GI tract, it is this lining that is continually bombarded by inflammatory immune cells seeking to destroy the invader. Once sufficiently sensitized, the immune response seems to continue even after the initial culprit has been destroyed.

There seems to be a genetic component to IBD because some breeds are more susceptible to the disease than others. Abnormalities in the dog's immune system, diet, and intestinal infections (these can be bacterial, viral, parasitic, or fungal in nature) are all thought to play a role in IBD.

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